| Pancreatic cancer is one of the common malignancies,with high degree of malignancyand poor prognosis,is known as "cancer of the King", and the morbidity and mortality ofpancreatic cancer has increased year by year. Because of insidious onset, early diagnosis isdifficult.more than80%of patients with locally advanced or metastatic have lesions atdiagnosis, which can not be resected through radical surgical,and the median survival timeis of only6-10months.If patients have a metastatic lesion,the median survival time willdrop to3-6months, the overall5-year survival rate is less than4%. Currently the standardtreatment for inoperable pancreatic cancer is limited to the choice of chemotherapy,radiotherapy or chemoradiotherapy. Because pancreatic cancers have low blood supplythan normal tissue, systemic chemotherapy can reach the tumor tissue from the treatmentdose is very small. If you blindly increase the dose of chemotherapy drugs topatients,systemic reactions such as nausea, vomiting, will become more unbearable, thus itwill reduce the quality of life of patients.With the popularity of endoscopic ultrasound technology, especially the emergenceand development of linear array EUS,and the use of the EUS guidance fine-needleaspiration biopsy in clinical, endoscopic ultrasound technology have transfrom the initialendoscopic ultrasound imaging technology into ultrasound-guided biopsy techniques.Since then, EUS has evolved from EUS imaging to EUS-FNA and wider applications. Sofar, there are several techniques based on pancreatic tumor endoscopic ultrasound-guidedpuncture technique,such as:Endoscopic ultrasound-guided fine needle injection technique,endoscopic ultrasound guided implantation of radioactive particles of iodine125,endoscopic ultrasound-guided radiofrequency ablation technology.Radiofrequency ablation technique is essentially a approach of hyperthermia, theprinciple is that particle friction and collisions in the electromagnetic fields can generatethermal effects.Since the1990s applied in medicine, radiofrequency ablation techniquepresents a good effect in terms of solid tumors.It has already been used in soft tissuetumors in the liver, lung, uterus, kidney, bone, breast, adrenal, thyroid and pancreas,itssafety and efficacy has been confirmed. Since radiofrequency ablation applied in the pancreatic cancer, the most common method of radiofrequency is performed in surgicallaparotomy, but this approach requires underwent open operation.And beforeradiofrequency ablation the pancreas needs to be separated from the surrounding tissue,which increases the complexity of the operation andextends the patient’s recoverytime.Addition,the patient will suffer from more trauma, various complications associatedwith open operation. initial studies suggest that, due to thecomplexity of adjacentanatomical structures of the pancreas, radiofrequency ablation of the pancreas may producesome common complications including acute pancreatitis, gastrointestinal bleeding, tissuedamage around the pancreas, bile leakage, pancreatic leakage, infection, ten duodenalobstruction and obstructive jaundice. Today, endoscopic ultrasound-guided radiofrequencyablation has combined high-resolution images with radiofrequency ablation, becauseultrasound can monitor pancreatic ducts, biliary ducts and blood vessels so clearly,thatablation procedure can avoid damage to these organizations as much as possible duringradiofrequency, which improves greatly the safety of radiofrequency ablation of thepancreas. Habib EUS-RFA catheter (EMcision Ltd,London) can pass smoothly through22G dedicated needle,and can perform radiofrequency ablation through endoscopicultrasound-guided puncture of the pancreas. Although the catheter has been used in clinical,it still lacks the standard formula of radiofrequency ablation damage range associated withpower and time. The purpose of this research is to learn more about thermal performanceof radiofrequency ablation of pancreatic tissue by Habib EUS-RFA catheter, as well as toexplore the feasibility, safety and effectiveness of its use in clinical.In order to use HabibEUS-RFA catheter in clinical safely and effectively, and provide a reliable treatment for thepatients with advanced pancreatic cancer,which can not be resected by radical surgery.The topics include about3parts:Part1An in vitro animal study of radiofrequency ablation of HabibEUS-RFA catheter in porcine pancreasObjective:Explore the thermal damage effect of radiofrequency ablation in pancreatic tissue indifferent power and time settings.Then gain the standard formula of radiofrequencyablation damage range associated with power and time through statistical analysis. Thusprovide a reliable basis for the clinical application of Habib EUS-RFA catheter in patients with unresectable pancreatic cancer.Methods:Radiofrequency ablation radiofrequency ablation performance depends on the RFpower and time, denoted by the parameter t and e. According to the results of preliminaryexperiments, the range of possible values of the power parameter of radiofrequencyablation is5watts (w) to20watts,5watts an increment (5w,10w,15w,20w), the range ofpossible values of the time parameter of radiofrequency ablation is40seconds(s) to240seconds, every20seconds an increment (40s,60s,80s,100s,120s,140s,160s,180s,200s,220s,240s) There are total11×4=44possible combinations according to each of thedifferent parameters, each combination executed twice, build a randomized table(usingSAS9.2statistical software) containing88combinations. According to RFA randomizationtable set parameters and perform continuous action in88pig pancreas in vitro,thenmeasure the range of ablation range with the naked eye, meanwhile,take the ablated tissuefor Histological examination.Then,use statistical methods to develop radiofrequencyablation equation.Results:Radiofrequency ablation in vitro porcine pancreas can produce significant tissuenecrosis, and with power enhancement and extension of time, the range of ablation willincrease correspondingly.Conclusions:Derived formula: Y (mm)=0.005×E2(w)+0.9374×ln [t (s)]-0.6943.Part2Research of endoscopic ultrasonography guidedradiofrequency ablation of pancreatic cancer of nude mouseObjective:Perform radiofrequency ablation on pancreatic cancer tissue of nude mice, verify theaccuracy of the radiofrequency ablation equation got in part1.Methods:Give subcutaneous inoculation of pancreatic cancer to20nude mices and feed2weeks. Take power (5w and10w,15w,20w) and time (40s,90s and90s,190s and240s) to build a randomization schedule.According to order of the randomization table，perform radiofrequency ablation on pancreatic cancer tissue of20nude mices, then kill20mices immediately to measure the ranges of ablation and take pathological examination.Statistical analysis is carried out on the test data to verify the accuracy of theradiofrequency ablation equation.Results:The radiofrequency ablation equation is suitable for living pancreatic cancertissue,and can be used to guide clinical application.Part3Clinical analysis of the preliminary application ofendoscopic ultrasound-guided radiofrequency ablationObjective:Preliminarily analyse feasibility, safety and effectiveness of the Habib EUS-RFAcatheter in clinical application of radiofrequency ablation of pancreatic cancer.Patients and Methods:6patients with pancreatic cancer which can not be resected through radical surgicalunderwent endoscopic ultrasound-guided radiofrequency ablation.Then observecomplications, pain changes, changes in tumor size of patients after treatment, survival ofthe patients.Results:Six patients successfully received application of endoscopic ultrasound-guidedradiofrequency ablation.No complication was observed. One patient(20%) have obviouspain relief, twopatients (40%) have mild pain relief, two patients(40%) have no painrelief.Lesion of one patient was significantly reduced, lesion of one patient was slightlyreduced, lesion of one patient have no reduction.5patients had died, the mean survival was4.6months, the longest6months, the shortest2months.Conclusions:Endoscopic ultrasound-guided radiofrequency ablation of pancreatic cancer has agood feasibility, safety and certain of effectiveness. |
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